Compare numeric values with a tolerance Math unit
1 function CompareValue(const A, B Integer|Int64):TValueRelationship;
2 function CompareValue (const A, B Single|Double|Extended; delta Single|Double|Extended:TValueRelationship;
CompareValue allows floating point numbers to be compared in a tolerant way. If the two numbers are close enough together, they are deemed to be equal. The delta value is the permitted tolerance.
There seems no point to the author in providing the Integer version of this function with no delta.
TValueRelationship supports the following values :
LessThanValue -1
EqualsValue 0
GreaterThanValue 1
Related commands
MaxGives the maximum of two integer values
MinGives the minimum of two integer values
MeanGives the average for a set of numbers
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Example code : Comparing floating point numbers
  A : Single;
  B : Single;
  C : Single;

  A := 23.0;
  B := 23.0;
  C := 23.1;

  // Compare 2 equal floats
  case CompareValue(A, B) of
    LessThanValue    : ShowMessage('A < B');
    EqualsValue      : ShowMessage('A = B');
    GreaterThanValue : ShowMessage('A > B');

  // Compare 2 unequal floats
  case CompareValue(A, C) of
    LessThanValue    : ShowMessage('A < C');
    EqualsValue      : ShowMessage('A = C');
    GreaterThanValue : ShowMessage('A > C');

  // Compare 2 unequal floats - but allow for a difference of up to +/- 0.2
  case CompareValue(A, C, 0.2) of
    LessThanValue    : ShowMessage('A < C');
    EqualsValue      : ShowMessage('A = C');
    GreaterThanValue : ShowMessage('A > C');
Show full unit code
  A = B
  A < C
  A = C
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